In one known method, for example as described in the introduction of French published certificate of utility number 2 471 181, a correcting and/or assisting sole is made by the following sequence of steps:
(a) taking a print of the sole of the foot in an approximately plane face of block of modelling clay;
(b) casting a rigid shape in said footprint;
(c) unmolding said shape; and
then bending over the shape a sheet of material, such as leather, suitable for plastically deforming and subsequently retaining the desired curvature, e.g. by applying a synthetic resin which is subsequently hardened or by gluing to a plate of cork having a correspondingly shaped hollow formed therein, then optionally adding corrective bumps to the sheet, and finally covering it with a leather insole.
This known method requires numerous operations, and is thus lengthy and expensive; further it suffers from requiring action both by an orthopedic doctor who is generally not capable of manufacturing the entire sole, but who is needed to specify the location and shape of any bumps that need adding, and by a prosthesis technician to build the sole in a workshop as a function of the doctor's prescription. Such two-stage action increases the time taken between the sole being prescribed, the patient trying it on, any necessary corrections being made to the added bumps, and final delivery of the sole.
To remedy these drawbacks, the above-mentioned certificate of utility proposes making an orthopedic sole by direct molding to the foot of the patient using a material which is suitable initially for deforming plastically to take up the required shape, and which is subsequently capable of solidifying rapidly.
This method does indeed have the advantage of being quick, firstly because the sole is made by direct molding, and secondly because the molding may be performed in the doctor's consulting room. However, it requires the patient to be present not only when a first sole is made for the patient, but also on every subsequent occasion on which the sole needs to be replaced.
Preferred implementations of the present invention remedy these drawbacks by proposing a method of making a correcting and/or assisting sole by molding in a manner which may be performed by the orthopedic doctor, i.e. by a method which does not require a great deal of time or equipment, and which also leaves the doctor or the technician with a rigid shape capable of being reused to renew the sole without requiring the patient to be present each time. In addition, the invention can be used to achieve these ends relatively cheaply.